This application claims the priority of Korean Patent Application No. 2002-86116, filed Dec. 28, 2002, in the Korean Intellectual Property Office, which is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a projection display apparatus using a color wheel such as a digital light processing projection television, and more particularly to a color wheel index aligning apparatus and an alignment method thereof.
2. Description of the Related Art
Generally, a projection display apparatus such as a digital light processing projection television uses a color wheel in order to separate light from a light source into color lights, in which a desired color is properly displayed on a screen of the display apparatus only when the reference color of the color wheel aligns with the color of the image signal processed at the projection display apparatus.
A reference point is indicated on the color wheel for aligning the respective starting positions of a corresponding image signal and the color wheel. A detection element is provided to detect the reference point. A reference point signal, the resultant signal of detecting the reference point, is provided to the image signal processor, and accordingly, the color of the image signal is made to align with the separated color from the color wheel by delaying the corresponding image signal at the image signal processor.
However, the respective positions of the detection element and the reference point of the color wheel often vary in respective lots due to errors made during an assembling process. Conventionally, in order to compensate for such variance, a delay of a color wheel index was manually adjusted by slightly varying the mounting position of the detection element. Since this method relies on the guesswork of the adjusting person, alignment was sometimes inaccurate if the adjuster changes, or due to various changes in surrounding conditions. Another problem was that it took a lengthy time for the alignment process.